Tom Imrich:
That's why airlines have been safely and successfully flying both RNP .1, and some GLS too, totally without SBAS, for well over a decade now.
What augmentation system are they using?
There are plenty of RNP .1 procedures out there, QANTAS, China Southern, and WestJet have many tailored procedures at this level.
No augmentation is required.
In regards to SBAS, I really dont ever see AUS investing in the stationary sats needed, nor the infrastructure to set this up. The US had 3, and when one died, they repositioned and reduced coverage area, and there are no plans to send up another.